package top.timestreet.xmsk.util;

import org.apache.commons.codec.binary.Base64;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;

/**
 * DES 加密类
 * 
 * @author Administrator
 *
 */
@Component
public class DESUtil {

	@Autowired
	private Environment environment;

	private static String key;

	@PostConstruct
	public void init() {
		key = environment.getProperty("des.key");
	}

	// 算法名称
	public static final String KEY_ALGORITHM = "DES";
	// 算法名称/加密模式/填充方式
	// DES共有四种工作模式-->>ECB：电子密码本模式、CBC：加密分组链接模式、CFB：加密反馈模式、OFB：输出反馈模式
	public static final String CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding";

	/**
	 * 
	 * 生成密钥key对象
	 * 
	 * @param keyStr 密钥字符串
	 * @return 密钥对象
	 * @throws InvalidKeyException
	 * @throws NoSuchAlgorithmException
	 * @throws InvalidKeySpecException
	 * @throws Exception
	 */
	private static SecretKey keyGenerator(String keyStr) throws Exception {
		byte input[] = HexString2Bytes(keyStr);
		DESKeySpec desKey = new DESKeySpec(input);
		// 创建一个密匙工厂，然后用它把DESKeySpec转换成
		SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
		SecretKey securekey = keyFactory.generateSecret(desKey);
		return securekey;
	}

	private static int parse(char c) {
		if (c >= 'a')
			return (c - 'a' + 10) & 0x0f;
		if (c >= 'A')
			return (c - 'A' + 10) & 0x0f;
		return (c - '0') & 0x0f;
	}

	// 从十六进制字符串到字节数组转换
	public static byte[] HexString2Bytes(String hexstr) {
		byte[] b = new byte[hexstr.length() / 2];
		int j = 0;
		for (int i = 0; i < b.length; i++) {
			char c0 = hexstr.charAt(j++);
			char c1 = hexstr.charAt(j++);
			b[i] = (byte) ((parse(c0) << 4) | parse(c1));
		}
		return b;
	}

	/**
	 * 加密数据
	 * 
	 * @param data 待加密数据
	 * @return 加密后的数据
	 */
	public static String encrypt(String data) {
		try {
			Key deskey = keyGenerator(key);
			// 实例化Cipher对象，它用于完成实际的加密操作
			Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
			SecureRandom random = new SecureRandom();
			// 初始化Cipher对象，设置为加密模式
			cipher.init(Cipher.ENCRYPT_MODE, deskey, random);
			byte[] results = cipher.doFinal(data.getBytes());
			// 该部分是为了与加解密在线测试网站（http://tripledes.online-domain-tools.com/）的十六进制结果进行核对
			// for (int i = 0; i < results.length; i++) {
			// System.out.print(results[i] + " ");
			// }
			// System.out.println();
			// 执行加密操作。加密后的结果通常都会用Base64编码进行传输
			return Base64.encodeBase64String(results);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 解密数据
	 * 
	 * @param data 待解密数据
	 * @return 解密后的数据
	 */
	public static String decrypt(String data) {
		try {
			Key deskey = keyGenerator(key);
			Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
			// 初始化Cipher对象，设置为解密模式
			cipher.init(Cipher.DECRYPT_MODE, deskey);
			// 执行解密操作
			return new String(cipher.doFinal(Base64.decodeBase64(data)));
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

}